Here is the full list of all 50 Ultra Savage achievements.
Reach Level 200
Defeat Unlimited Nightmare Error
Enhanced Item +20
Defeat Dr. Congo
Defeat Unlimited Error
Defeat Error
Have Over 10'000'000 HP
Made A Costume
Defeat Oreb and Zeeb
Reach Level 180
Defeat Githeon The Galactic Conqueror
Have Over 300% ATK SPD
Defeat Xoreb
Deal Over 10'000'000 Damage
Reach Level 160
Have Over 50% CRIT
Do Ten Time Travels
Enhanced Item +10
Reach Level 140
Have Over 1'000'000 HP
Defeat Nahash
Do Six Time Travels
Deal Over 1'000'000 Damage
Defeat King Bera the Reaper
Reach Level 100
Defeat Lord Pretty Face Coolinagi
Have Over 100 CHI
Reach Level 80
Have Over 100,000 HP
Enhanced Item +6
Do Your Second Time Travel
Deal Over 100'000 Damage
Defeat Raki-Raki The Demolisher
Enhanced Item +3
Reach Level 60
Deal Over 9'000 Damage
Defeat Liki Lee The Amgi-Turner
Do Your First Time Travel
Defeat Heli Boss
Deal Over 1'00 Damage
Maxed Out A Skill
Have Over 150% ATK SPD
Reach Fusion Level 10
Reach Level 30
Defeat Prince of Madness
First Enhancement
Reach Level 10
Equip a blade and meet Kairon
Have over 3'00 HP
Do your first fusion